BiquadFilterNode()

The BiquadFilterNode() constructor of the Web Audio API creates a new BiquadFilterNode object, which represents a simple low-order filter, and is created using the AudioContext.createBiquadFilter() method.

Syntax

var biquadFilterNode = new BiquadFilterNode(context, options)

Parameters

Inherits parameters from the AudioNodeOptions dictionary.

context
A reference to an AudioContext.
options Optional
Options are as follows:
  • type: One of "lowpass", "highpass", "bandpass", "lowshelf", "highshelf", "peaking", "notch", "allpass". The meaning of the other options depends on the value of this one. The defaults for all are as follows:
    • Q: 1
    • detune: 0
    • frequency: 350
    • gain: 0

lowpass: (Default) Allows frequencies below a cutoff frequency to pass through, and attenuates frequencies above the cutoff. This is a standard second-order resonant lowpass filter with 12dB/octave rolloff.

  • Q: Controls how peaked the response will be at the cutoff frequency. A large value makes the response more peaked. Please note that for this filter type, this value is not a traditional Q, but is a resonance value in decibels.
  • frequency: The cutoff frequency.
  • gain: Not used.

highpass: A highpass filter is the opposite of a lowpass filter. Frequencies above the cutoff frequency are passed through, but frequencies below the cutoff are attenuated. It implements a standard second-order resonant highpass filter with 12dB/octave rolloff.

  • Q: Controls how peaked the response will be at the cutoff frequency. A large value makes the response more peaked. Please note that for this filter type, this value is not a traditional Q, but is a resonance value in decibels.
  • frequency: The cutoff frequency.
  • gain: Not used.

bandpass: A bandpass filter allows a range of frequencies to pass through and attenuates the frequencies below and above this frequency range. It implements a second-order bandpass filter.

  • Q: Controls the width of the band. The width becomes narrower as the Q value increases.
  • frequency: The center of the frequency band.
  • gain: Not used.

lowshelf: The lowshelf filter allows all frequencies through, but adds a boost (or attenuation) to the lower frequencies. It implements a second-order lowshelf filter.

  • Q: Not used.
  • frequency: The upper limit of the frequences where the boost, or attenuation, is applied.
  • gain: The boost, in dB, to be applied. If the value is negative, the frequencies are attenuated.

highshelf: The highshelf filter is the opposite of the lowshelf filter and allows all frequencies through, but adds a boost to the higher frequencies. It implements a second-order highshelf filter.

  • Q: Not used.
  • frequency: The lower limit of the frequences where the boost, or attenuation, is applied.
  • gain: The boost, in dB, to be applied. If the value is negative, the frequencies are attenuated.

peaking: The peaking filter allows all frequencies through, adding a boost, or attenuation, to a range of frequencies.

  • Q: The width of the band of frequencies that are boosted. A large value implies a narrow width.
  • frequency: The center frequency of the boost range.
  • gain: The boost, in dB, to be applied. If the value is negative, the frequencies are attenuated.

notch: The notch filter (also known as a band-stop, or band-rejection filter) is the opposite of a bandpass filter. It allows all frequencies through, except for a set of frequencies.

  • Q: The width of the band of frequencies that are attenuated. A large value implies a narrow width.
  • frequency: The center frequency of the attenuation range.
  • gain: Not used.

allpass: An allpass filter allows all frequencies through, but changes the phase relationship between the various frequencies. It implements a second-order allpass filter.

  • Q: The sharpness of the phase transition at the center frequency. A larger value implies a sharper transition and a larger group delay.
  • frequency: The frequency where the center of the phase transition occurs. Viewed another way, this is the frequency with maximal group delay.
  • gain: Not used.

Return value

A new BiquadFilterNode object instance.

Specifications

Specification Status Comment
Web Audio API
The definition of 'BiquadFilterNode()' in that specification.
Working Draft Initial definition.

Browser Compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 55
Notes
Full support 55
Notes
Notes Before Chrome 59, the default values were not supported.
Edge ? Firefox Full support 53IE No support NoOpera Full support 42
Notes
Full support 42
Notes
Notes Before Opera 46, the default values were not supported.
Safari ? WebView Android Full support 55
Notes
Full support 55
Notes
Notes Before version 59, the default values were not supported.
Chrome Android Full support 55
Notes
Full support 55
Notes
Notes Before Chrome 59, the default values were not supported.
Edge Mobile ? Firefox Android Full support 53Opera Android Full support 42
Notes
Full support 42
Notes
Notes Before Opera 46, the default values were not supported.
Safari iOS ? Samsung Internet Android Full support 6.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
See implementation notes.
See implementation notes.

Document Tags and Contributors

Last updated by: sideshowbarker,